How to round JavaScript value to 2 decimals?

General Discussions
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1

JavaScript math, round to two decimal places

I have the following JavaScript syntax:

var discount = Math.round(100 - (price / listprice) * 100); This rounds up to the whole number. How can I return the result with two decimal places?

2

I’ve been working with JavaScript for over a decade, and one of the simplest ways to handle precise rounding is using toFixed(). So if you’re looking to javascript round to two decimal places, here’s a reliable method I often use:

var discount = (100 - (price / listprice) * 100).toFixed(2);

This gives you a string value with exactly two decimal places. If you’re using it in further calculations, you’ll want it as a number:

var discount = parseFloat((100 - (price / listprice) * 100).toFixed(2));

Clean and effective for formatting values like percentages or prices.

3

Yeah, I’ve had similar scenarios in frontend projects. Just to add to what @mark-mazay said—if you’re formatting values consistently across a UI, especially for display, using toFixed(2) is pretty much the go-to. It ensures you always get a two-decimal format—even for whole numbers.

So when doing a javascript round to two decimal places, you’re not just rounding; you’re standardizing how the value appears, which is great for things like price tags:

var discount = (100 - (price / listprice) * 100).toFixed(2); // "25.00" instead of "25"

And yeah, convert it with parseFloat() only when you need to do math again.

4

Totally agree with both of you. From my time working on eCommerce dashboards, consistent formatting was critical—especially when syncing prices across currencies. One nuance I’d highlight when doing a javascript round to two decimal places is understanding that toFixed() handles rounding internally (not just trimming).

So this:

var discount = parseFloat((100 - (price / listprice) * 100).toFixed(2));

…isn’t just formatting—it’s giving you a properly rounded value to two decimals. Perfect for things like tax, discounts, or conversions where precision matters.